Surface Of Integument Research Articles

Evidence of inherent spontaneous polarization in the metazoan integument epithelia

The live integument epithelia of the metazoa have an inherent spontaneous polarization (an inherent permanent electric dipole moment) of corresponding direction perpendicular to the integument surface. The existence of the inherent polarization was proved by their temperature dependence, i.e., by the pyroelectric (PE) effect. Quantitative PE measurements were carried out on a number of integument epithelia of vertebrates (a) in vivo, (b) on fresh epidermis preparations, and (c) on dead, air-dried epidermis specimens of the same species. The demonstrated spontaneous polarization is not dependent on the living state and not caused by a potential difference between the outer and inner integument surface. Dead, dry epidermis samples (potential difference less than 0.01 mV) as well as dead, dry integument appendages (bristles, hairs), and dead cuticles (of arthropoda, annelida, nematoda) showed an inherent dipole moment of the same orientation as the live epidermis. The findings reveal a relationship between the direction (vector) of inherent spontaneous polarization and that of growth (morphogenesis) in the animal epidermis, their appendages, and cuticles. We conclude (a) that the inherent spontaneous polarization is present in live individual epithelial cells of the metazoan integument, and (b) that this physical property is related to the structural and functional cell polarity of integument epithelia and possibly of other epithelia.

Recognition of Individuals by Vervet Monkeys

bromeliads (Tillandsia), epiphytes often occupied by typical plethodontids in tropical cloud forest, temperatures varied spatially by no more than 2?C at any one time and by no more than 2.5?C throughout a day (Figure lb). A similar pattern is evident within a characteristic microhabitat of tropical salamanders at low elevations, the outermost leaf axils of banana plants (Musa). The banana plant that was studied was more diverse in microclimates than the bromeliads considered previously. Temperatures beneath the outermost leaf sheaths differed by 2.2-3.7?C from the sunlit to the shaded side of the plant. Nonetheless, compared with the range of temperatures in the habitat at large, this range was small. The limited thermal diversity of typical salamander microhabitats is in accord with the findings of a companion study, which also suggest that tropical (and temperate) salamanders are often unable to exercise a thermal preference because of thermal homogeneity. Also in Ecology 63(6), Feder and Lynch reported that body temperatures of plethodontid salamanders varied regularly and consistently with altitudinal, latitudinal, and seasonal changes in temperature. Even so, plethodontids seldom experience extreme temperatures, perhaps because the moist microhabitats to which plethodontids are restricted are generally moderate in temperature (Figure lb). This study emphasizes the extent to which the hydric relations of amphibians may structure many other aspects of their biology. Because of their permeable integument and high surface to volume ratio, plethodontid salamanders may be unable to exploit more exposed microhabitats in which temperature selection might be feasible or to bask without incurring lethal desiccation. Physiological rather than behavioral compensation for changes in body temperature may thus be especially important to lungless salamanders. i of a PBT from a diversity of temperatures. W thin liads (Ti landsia), epiphytes often occupied b typical ontids in tropical cloud forest, temperatures varied i ll by no more than 2?C at any one time and by no more .5?C throughout a day (Figure lb). A s milar pattern is t ithin a characteristic microhabitat of tropical sala-

The surface microstructure of marine and terrestrial isopoda (Crustacea, Peracarida)

The microstructure of the surface of thirteen marine littoral and two terrestrial isopods was investigated by scanning electron microscopy. A great diversity of surface ornamentation is present, including non-sensory microscales, pits, tubercles, and ridges, and sensory tricorns, pit organs, pores, papillae and setae. Microscales are common features of the integument surface; their shape and size are highly variable. Tricorns were not observed on the marine littoral isopods. Several hitherto undescribed structures were observed including spade-like projections from the tergite surface of Oniscus asellus, hair-like filaments associated with the microscales of Jaera and ridged conical protuberances on Edotea triloba and E. montosa. The possible function of certain surface microstructures is discussed.

Evidence for pyroelectric and piezoelectric sensory mechanisms in the insect integument

Quantitative pyroelectric (PE) and piezoelectric (PZE) measurements were carried out on the insect integument of live Blaberus giganteus (cockroach) and on dry integument preparations of the same species. Voltage responses to optical pulses of 10--500 ms, absorbed in the live integument, were PE: interference filter measurements showed the responses to be proportional to the absorbed thermal radiation flux and independent of the wavelength. The voltage/time-course of the responses was in agreement with theoretically calculated PE signals. Voltage responses to mechanical pulses were PZE. The responses of the inner and outer integument surfaces always had opposite electric signs. The polar character of the integument was confirmed by means of a separate dielectric heating method. To explain these results, we hypothesize that the PE properties are for the most part localized in the two outermost layers (outer and inner epicuticle) of the integument, which consists mainly of polar lipids and proteins. Parallel alignment of these polar molecules perpendicular to the integument surface is very likely. PE and PZE responses, therefore, will not only occur in live insects but will also be measurable in dead, dry integument preparations as long as the polar tissue texture remains intact. Due to its polar texture, the insect integument will react to rapid changes in temperature, illumination, or uniaxial pressure in the same way as nonbiological PE materials, where the voltage responses depend on dX/dt (X, pressure or temperature). It seems clear, therefore, that the well-known physiological reactions of various arthropods to such physical outside influences may be related to the PE property of their integument.

The transport of L‐alanine by the integument of the marine polychaete, Glycera dibranchiata

AbstractThe unidirectional influx of14C‐L‐alanine into the external integument surface of Glycera dibranchiata was measured in the presence and absence of sodium using lucite influx chambers which permitted brief exposures of only the external surface of the body wall to isotope. The influx of alanine was the sum of a mediated component obligatorily dependent on sodium in the external medium, and a nonsaturable sodium‐independent diffusion component. The mediated component was inhibitable by other amino acids, lacked transconcentration effects, and had a Q10 of 9.64 near the acclimation temperature of 12°C. The diffusion component was not competitively inhibitable and had a Q10 of 0.99 at 12°C. The saturable component had a Kt = 8.63 × 10−5 M and Jmax = 1.38 × 10−7 mol/hr · cm2. The Kt falls within the physiological range of free amino acid concentrations to which the worm would be exposed in its habitat.